1. Field of Invention
This invention relates to but is not him limited shielding devices, specifically to a retractable multi-piece cover for use over a subcutaneously implanted port which extends during removal of a needle from the port so as to surround the needle as it is withdrawn from the patent so that the person removing the needle is protected from spattering blood and possible needle stick resulting from needle rebound. Applications may include, but are not limited to, use over subcutaneously arm-implanted ports and subcutaneously chest-implanted ports, and other indewelling needle systems used in clinical settings.
2. Description of Prior Art
Historically, long-term therapy treatments involving the intravenous administration of medications have presented patents with a variety of apprehensions and problems. Even when treatment was lengthy, or repeated often, delivery of the medications occurred through repeated injections into the small veins of the patient, such as those in the patient's arm. Repeated needle punctures into the patient's veins often caused pain, as well as injury to the patient's veins. Also, some medications themselves were known to injure the small veins. Additional needle punctures, resulting from the withdrawal of blood from the patient, were also needed to monitor the effect of the medication on the patient. Anxiety in patients prior to therapy treatments was common.
Catheters were developed for the direct administration of medications into a patient through the large vein near the patient's heart. Such direct administration allows for faster circulation of medication within the patient's system, and prevents injury to small veins which repeated needle punctures and concentrated medications may cause. Two types of catheters have been developed for use in central venous therapy. One is the external catheter which has a small piece of flexible tubing with a connector on one of its ends. Part of the tubing and the connector remain outside of the patient's body. The other end of the tubing is placed into the large vein near the heart. The external catheter is commonly placed into the patient's arm or the patient's chest and may be covered with a sterile covering between therapy treatments. After the external catheter is installed through the patient's skin, a syringe or other delivery device is used for infusing medication into the patent through the external connector. Disadvantages of external catheters is that maintenance is required to minimize infection around the opening in the patent's skin through which the catheter protrudes. Also, periodic flushing is required to keep external catheters open and the patent's activity may be restricted.
The other type of catheter for central venous access is surgically positioned within a patient, between the large vein near the heart and a subcutaneously implanted port. No part of the second type of central venous access protrudes through the skin of the patient. The subcutaneously implanted ports are commonly chest-placed, or arm-placed, so as to minimally restrict a patient's activity. The ports also have a self-sealing septum through which a needle may be inserted for delivery of medications. Blood samples may also be withdrawn through such ports. A needle may remain in a septum for a period of time to allow for an optimum flow-rate of medication into the patient. Ports usually involve little or no activity restriction and minimal maintenance. Further, the small hump made by a port under the patent's skin is less noticeable than a connector attached to a protruding piece of tubing. One problem associated with such ports develops upon removal of the needle from the port. When pressure is exerted on the angled needle to remove it from the port, frictional resistance may cause the needle to temporarily bind against the septum, requiring the person removing it to exert additional force to withdraw the needle. When the needle finally releases from the septum, a downward needle rebound develops which may cause the needle to penetrate the skin of the person withdrawing the needle, or the skin of the patient. The present invention eliminates the problems associated with needle rebound and also protects the person removing the needle from patient's blood which may spatter during removal of the needle from these instances and other healthcare giver needle use situations involving many types of systems.
The prior art known to be most closely related to the present invention are the inventions disclosed in U.S. Pat. No. 5,187,815 to Medev Corporation (1993) and U.S. Pat. No. 5,342,311 to Darina (1994). The Medev Corporation invention discloses a needlestick protective glove which would protect the fingers of a person removing a medication delivery needle from a subcutaneously implanted port. The Darina skin shield invention discloses a flexible annular disc having finger tabs and a central disc opening. The disc is thick enough to resist needle penetration. The finger tabs help a person removing a needle from a subcutaneously implanted port to apply pressure to the site of the implanted port for site stabilization so that the disc will help to protect the persons fingers from accidental needle stick during needle rebound. In contrast to the Medev Corporation and the Darina inventions, the present invention extends upon needle removal to surround the area above the port, through which the needle travels during its removal from the port, to prevent accidental needle penetration into the person removing it, or into the patient during needle rebound. Many healthcare workers who wear gloves often and develop sensitive skin from repeatedly wearing gloves would prefer to use the present invention instead of the Medev Corporation invention. Also, since the present invention completely needle tip surrounds a after it is removed from the patent, the present invention would protect the person removing it from accidental needle stick resulting from needle rebound better than a disc which merely covers the port site.